README: document how to try out Websockets

Closes #295

Author: Christian Beier

README.md

@@ -271,6 +271,16 @@ There is also an array named "richSource" for colourful cursors. They have
 the same format as the frameBuffer (i.e. if the server is 32 bit,
 a 10x4 cursor has 4x10x4 bytes).
 
+Using Websockets
+----------------
+
+You can try out the built-in websockets support by starting the example server
+from the build directory via `examples/example`. It's important to _not_ start
+from within the `examples` directory as otherwise the server program won't find
+its HTTP index file. The server program will tell you a URL to point your web
+browser to. There, you can click on the noVNC-Button to connect using the bundled
+noVNC viewer.
+
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